package com.bsit.obu.utils;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.security.SecureRandom;

/**
 * 3DES加密工具类
 */
public class EncryptUtils {
    // 密钥(DES加密和解密过程中，密钥长度都必须是8的倍数)
    private final static String secretKey = "ucserver";

    // 加解密统一使用的编码方式
    private final static String encoding = "utf-8";
    private final static String ALGORITHM = "DES";

    /**
     * 3DES加密
     *
     * @param plainText 普通文本
     * @return
     * @throws Exception
     */
    public static String encode(String plainText) throws Exception {
        // DES算法要求有一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(secretKey.getBytes());
        // 创建一个密匙工厂，然后用它把DESKeySpec转换成
        // 一个SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");//DES加密和解密过程中，密钥长度都必须是8的倍数
        SecretKey secretKey = keyFactory.generateSecret(dks);
        // using DES in ECB mode
        Cipher cipher = Cipher.getInstance("DES/ECB/pkcs5padding");
        // 用密匙初始化Cipher对象
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, sr);
        // 执行加密操作
        byte[] encryptData = cipher.doFinal(plainText.getBytes(encoding));
        return Base64.encode(encryptData);
    }

    /**
     * 3DES解密
     *
     * @param encryptText 加密文本
     * @return
     * @throws Exception
     */
    public static String decode(String encryptText) throws Exception {
        // DES算法要求有一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
        // 从原始密匙数据创建一个DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(secretKey.getBytes());
        // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成
        // 一个SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey secretKey = keyFactory.generateSecret(dks);
        // using DES in ECB mode
        Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

        // 用密匙初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, secretKey, sr);
        // 正式执行解密操作
        byte[] decryptData = cipher.doFinal(Base64.decode(encryptText));
        return new String(decryptData, encoding);
    }

    public static String padding(String str) {
        byte[] oldByteArray;
        try {
            oldByteArray = str.getBytes("UTF8");
            int numberToPad = 8 - oldByteArray.length % 8;
            byte[] newByteArray = new byte[oldByteArray.length + numberToPad];
            System.arraycopy(oldByteArray, 0, newByteArray, 0,
                    oldByteArray.length);
            for (int i = oldByteArray.length; i < newByteArray.length; ++i) {
                newByteArray[i] = 0;
            }
            return new String(newByteArray, "UTF8");
        } catch (UnsupportedEncodingException e) {
            System.out.println("Crypter.padding UnsupportedEncodingException");
        }
        return null;
    }

    /**
     * Base64编码工具类
     */
    public static class Base64 {
        private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_".toCharArray();

        public static String encode(byte[] data) {
            int start = 0;
            int len = data.length;
            StringBuffer buf = new StringBuffer(data.length * 3 / 2);

            int end = len - 3;
            int i = start;
            int n = 0;

            while (i <= end) {
                int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 0x0ff) << 8) | (((int) data[i + 2]) & 0x0ff);
                buf.append(legalChars[(d >> 18) & 63]);
                buf.append(legalChars[(d >> 12) & 63]);
                buf.append(legalChars[(d >> 6) & 63]);
                buf.append(legalChars[d & 63]);
                i += 3;
                if (n++ >= 14) {
                    n = 0;
                    buf.append(" ");
                }
            }
            if (i == start + len - 2) {
                int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 255) << 8);
                buf.append(legalChars[(d >> 18) & 63]);
                buf.append(legalChars[(d >> 12) & 63]);
                buf.append(legalChars[(d >> 6) & 63]);
                buf.append("=");
            } else if (i == start + len - 1) {
                int d = (((int) data[i]) & 0x0ff) << 16;
                buf.append(legalChars[(d >> 18) & 63]);
                buf.append(legalChars[(d >> 12) & 63]);
                buf.append("==");
            }
            return buf.toString();
        }
        private static int decode(char c) {
            if (c >= 'A' && c <= 'Z')
                return ((int) c) - 65;
            else if (c >= 'a' && c <= 'z')
                return ((int) c) - 97 + 26;
            else if (c >= '0' && c <= '9')
                return ((int) c) - 48 + 26 + 26;
            else
                switch (c) {
                    case '-':
                        return 62;
                    case '_':
                        return 63;
                    case '=':
                        return 0;
                    default:
                        throw new RuntimeException("unexpected code: " + c);
                }
        }

        /**
         * Decodes the given Base64 encoded String to a new byte array. The byte array holding the decoded data is returned.
         */
        public static byte[] decode(String s) {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            try {
                decode(s, bos);
            } catch (IOException e) {
                throw new RuntimeException();
            }
            byte[] decodedBytes = bos.toByteArray();
            try {
                bos.close();
                bos = null;
            } catch (IOException ex) {
                System.err.println("Error while decoding BASE64: " + ex.toString());
            }
            return decodedBytes;
        }

        private static void decode(String s, OutputStream os) throws IOException {
            int i = 0;
            int len = s.length();
            while (true) {
                while (i < len && s.charAt(i) <= ' ')
                    i++;
                if (i == len)
                    break;
                int tri = (decode(s.charAt(i)) << 18) + (decode(s.charAt(i + 1)) << 12) + (decode(s.charAt(i + 2)) << 6) + (decode(s.charAt(i + 3)));
                os.write((tri >> 16) & 255);
                if (s.charAt(i + 2) == '=')
                    break;
                os.write((tri >> 8) & 255);
                if (s.charAt(i + 3) == '=')
                    break;
                os.write(tri & 255);
                i += 4;
            }
        }
    }

    public static void main(String[] args) throws Exception {
        String plainText = "[{\"user\":\"402892ee59b6e6930159b6e849740000\",\"mobile\":\"18205189527\"}]";
        String encryptText = EncryptUtils.encode(plainText).replace(" ", "");
        System.out.println(encryptText);
        System.out.println(EncryptUtils.decode(encryptText));
    }

    private static boolean isEmpty(String str){
        return str == null || str.trim().equals("");
    }


    /**
     * 计算MAC算法
     *
     * @param source
     *            源字符串
     * @param key
     *            密钥
     * @return
     */
    public static String calculateMac(String source, String key) {
        if(isEmpty(source) || isEmpty(key)){
            return "source data or key data can't be null!";
        }
        if (32 != key.length()) {
            return "key length error! need:32, actural:" + key.length();
        }
        /*
         * if (0 != (source.length() % 16)) { return "source length error!"; }
         */
        source = fixSourceData(source);

        // 待加密数据明文对应的BCD码
        byte[] sourceBt = CodeConvertUtils.ASCII_To_BCD(source.getBytes());
        // 加密密钥BCD码
        byte[] keyBt = CodeConvertUtils.ASCII_To_BCD(key.getBytes());

        return calculateMac(sourceBt, keyBt);
    }

    /**
     *
     * 对源数据补足8字节的整数倍
     *
     * @author zhufeng.zhang
     * @param sourceStr
     * @return
     *
     */
    private static String fixSourceData(String sourceStr) {
        int remainder = sourceStr.length() % 16;
        StringBuilder sb = new StringBuilder(sourceStr);
        if (remainder != 0) {
            int length = 16 - remainder;
            if (length != 0) {
                for (int i = 0; i < length; i++) {
                    if (0 == i) {
                        sb.append("8");
                    } else {
                        sb.append("0");
                    }
                }
            }
        }
        return sb.toString();
    }

    /**
     * 计算MAC算法
     *
     * @param source
     *            源字符串
     * @param key
     *            密钥
     * @return
     */
    public static String calculateMac(byte[] source, byte[] key) {
        if (16 != key.length) {
            return "key length error! need:32, actural:" + key.length;
        }
        if (0 != (source.length % 8)) {
            return "source length error!";
        }

        int times = source.length / 8;
        // 加密密钥前8位
        byte[] keyLeft = EncryptUtils.distributeBytes(key, 0);
        // 加密密钥后8位
        byte[] keyRight = EncryptUtils.distributeBytes(key, 1);
        byte[] initData = { 0, 0, 0, 0, 0, 0, 0, 0 };

        for (int i = 0; i < times; i++) {
            initData = EncryptUtils.xor(initData, source, i);
            initData = EncryptUtils.ecbEncrypt(initData, keyLeft);
        }
        initData = EncryptUtils.ecbDecrypt(initData, keyRight);
        initData = EncryptUtils.ecbEncrypt(initData, keyLeft);

        String outString = CodeConvertUtils.BCD_To_Str(initData);

        return outString.substring(0, 8);
    }


    /**
     * 把by按照8字节数组进行拆分
     */
    public static byte[] distributeBytes(byte[] by, int j) {
        byte[] b = new byte[8];
        for (int i = 0; i < 8; i++) {
            b[i] = by[i + j * 8];
        }
        return b;
    }

    /**
     * 将a与b进行按位异或
     */
    public static byte[] xor(byte[] a, byte[] b, int j) {
        byte[] rb = new byte[a.length];
        for (int i = 0; i < a.length; i++) {
            rb[i] = (byte) (a[i] ^ b[j * 8 + i]);
        }
        return rb;
    }

    /**
     * 加密
     *
     * @param datasource
     *            byte[]
     * @param password
     *            String
     * @return byte[]
     */
    public static byte[] ecbEncrypt(byte[] datasource, byte[] password) {
        try {
            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
            random.setSeed(datasource);
            DESKeySpec desKey = new DESKeySpec(password);
            // 创建一个密匙工厂，然后用它把DESKeySpec转换成
            SecretKeyFactory keyFactory = SecretKeyFactory
                    .getInstance(ALGORITHM);
            SecretKey securekey = keyFactory.generateSecret(desKey);
            // Cipher对象实际完成加密操作
            Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding");
            // 用密匙初始化Cipher对象
            cipher.init(Cipher.ENCRYPT_MODE, securekey, random);
            // 现在，获取数据并加密
            // 正式执行加密操作
            return cipher.doFinal(datasource);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 解密
     *
     * @param src
     *            byte[]
     * @param password
     *            String
     * @return byte[]
     * @throws Exception
     */
    public static byte[] ecbDecrypt(byte[] src, byte[] password) {
        byte[] a = {};
        Cipher cipher = null;
        try {
            // DES算法要求有一个可信任的随机数源
            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
            random.setSeed(src);
            // 创建一个DESKeySpec对象
            DESKeySpec desKey = new DESKeySpec(password);
            // 创建一个密匙工厂
            SecretKeyFactory keyFactory = SecretKeyFactory
                    .getInstance(ALGORITHM);
            // 将DESKeySpec对象转换成SecretKey对象
            SecretKey securekey = keyFactory.generateSecret(desKey);
            // Cipher对象实际完成解密操作
            cipher = Cipher.getInstance("DES/ECB/NoPadding");
            // 用密匙初始化Cipher对象
            cipher.init(Cipher.DECRYPT_MODE, securekey, random);
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 真正开始解密操作
        try {
            a = cipher.doFinal(src);
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e1) {
            e1.printStackTrace();
        }
        return a;
    }


}
